Specific endocrine syndromes are produced in response to benign and malignant tumors of endocrine tissue. We have been part of a collaborative group in the Clinical Center, NCI, and NINDS to study these tumors. We study patients with acromegaly in collaboration with Dr. Russell Lonser in neurosurgery at NIH. These studies consist of careful phenotypic characterization of the patient followed by surgery to remove the adenoma. This is followed by histologic and molecular genetic characterization so that phenotypic-genotypic characterization can be made. The second group of studies is in collaboration with Dr. Electron Kebebew in which a similar group of phenotypic-genotypic characterization is underway. In addition, Clinical Center Radiology is involved in collaboration to localize the pancreatic tumors for surgical localization. These tumors have also been used as a resource by other investigators in NIDDK, by other institutes and by NCI pathology.